Histologic Outcomes After Guided Bone Regeneration of Peri-implant Defects Comparing Individually Shaped Block Versus Particulate Bone Substitutes.

Peri-implant bone dehiscences were grafted either with deproteinized bovine bone mineral (DBBM) block or with particulate DBBM, both covered with a collagen membrane and stabilized with resorbable pins. After 6 months, 17 biopsy samples were included for histologic assessment. Block and particulate DBBM rendered successful tissue integration. Particulate DBBM showed a median of 25.2% of new bone and 31.3% of bone substitute. In the block group, there was a median of 11.5% of new bone and 36.0% of bone substitute. When interpreting the discrepancy in new bone between the groups, the difference in the size of the augmented hard tissue needs to be taken into account.

Randomized Controlled Clinical Trial of All-Ceramic Single-Tooth Implant Reconstructions Using Modified Zirconia Abutments: Results at 5 Years After Loading.

The objective of this trial study was to assess whether submucosal veneering of internally connected zirconia abutments influences clinical, radiographic, and technical outcomes of single-tooth implant-borne reconstructions at 5 years after loading. A total of 20 patients with 20 single-tooth implants in the anterior or premolar area of the maxilla or mandible were included. The implants were randomly restored with fixed single-tooth reconstructions using either pink-veneered customized zirconia abutments (test group = 10) or nonveneered customized zirconia abutments (control group = 10). All reconstructions were adhesively cemented with all-ceramic crowns. Follow-up examinations were performed at baseline (7 to 10 days after crown insertion) and at 1, 3, and 5 years after loading, at which points the following were assessed: periodontal parameters such as probing depth (PD), bleeding on probing (BOP), and marginal bone levels, as well as technical outcomes using the modified United States Public Health Service (USPHS) criteria. Statistical comparisons were based on the Wilcoxon-Mann-Whitney test. Sixteen patients attended the 5-year follow-up. At 5 years, the implant survival rate was 100% and the prosthetic survival rate was 94.1% (one abutment fracture in the test group). Veneering of the submucosal part of zirconia abutments resulted in significantly higher mean PD values: 3.6 ± 0.4 mm (test group) and 3.0 ± 0.5 mm (control group), P = .042. Marginal bone levels at 5 years and changes up to 5 years were not significantly different between groups (P > .05). One crown exhibited an abutment fracture and two crowns a minor chipping (17.6% overall technical complication rate). Limited by a small sample size, veneering of the submucosal part of internally connected zirconia abutments led to outcomes that were less favorable biologically (PD, BOP, and KM), but similar to nonveneered abutments radiographically and technically.

Effects of hypericin and a chlorin based photosensitizer alone or in combination in squamous cell carcinoma cells in the dark.

INTRODUCTION: The toxic influence of photosensitizers in the dark is poorly investigated. In our study we used the photosensitizers liposomal meso-tetrahydroxyphenyl chlorin derivative (Foslipos(®)) and hypericin as well as their 1:1 combination on two different head and neck squamous cell carcinoma (HNSCC) cell lines (UMB-SCC 745 and UMB-SCC 969). MATERIALS AND METHODS: We examined uptake, efflux and localization of the photosensitizers with confocal microscopy. Fluorescence quantification was measured with a micro-plate spectrometer. Special interest was given to effects on cell proliferation (BrdU proliferation assay), RNA quality (Bioanalyzer measurements) and DNA damage (comet assays) in the dark. RESULTS: Foslipos(®) uptake was linear over time and its efflux was not achieved even after 24 h while uptake of hypericin reached a plateau after 5 h and was almost eliminated after 24 h. Localization of Foslipos(®) was organelle-unspecific. Hypericin was found mainly at membranes and in trans-golgi network. Foslipos(®) treated cells showed cell toxicity for the highest concentration (10 µg/mL). In contrast, hypericin was toxic for all concentrations (10-0.6 µg/mL). The photosensitizer combination was non-toxic for all concentrations (10-0.6 µg/mL). No changes in RNA quality were monitored. Initial DNA damage was found only in hypericin treated UMB-SCC 745, which recovered after 3h. No significant DNA damage was found for UMB-SCC 969. CONCLUSION: Our data shows that the combinatorial application decrease photosensitizer toxicity, which can be advantageous in PDT treatments.